[PATCH 4/7] cifs: Add a function to read into an iter from a socket

From: David Howells
Date: Tue Aug 23 2022 - 13:01:11 EST


Add a helper function to read data from a socket into the given iterator.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Steve French <sfrench@xxxxxxxxx>
cc: Shyam Prasad N <nspmangalore@xxxxxxxxx>
cc: Rohith Surabattula <rohiths.msft@xxxxxxxxx>
cc: linux-cifs@xxxxxxxxxxxxxxx
---

fs/cifs/cifsproto.h | 3 +++
fs/cifs/connect.c | 16 ++++++++++++++++
2 files changed, 19 insertions(+)

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 3bc94bcc7177..ba19f9b03fc6 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -241,6 +241,9 @@ extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,
unsigned int page_offset,
unsigned int to_read);
extern int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb);
+extern int cifs_read_iter_from_socket(struct TCP_Server_Info *server,
+ struct iov_iter *iter,
+ unsigned int to_read);
extern int cifs_match_super(struct super_block *, void *);
extern int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx);
extern void cifs_umount(struct cifs_sb_info *);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 3da5da9f16b0..b81853846bd5 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -795,6 +795,22 @@ cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
return cifs_readv_from_socket(server, &smb_msg);
}

+int
+cifs_read_iter_from_socket(struct TCP_Server_Info *server, struct iov_iter *iter,
+ unsigned int to_read)
+{
+ struct msghdr smb_msg;
+ int ret;
+
+ smb_msg.msg_iter = *iter;
+ if (smb_msg.msg_iter.count > to_read)
+ smb_msg.msg_iter.count = to_read;
+ ret = cifs_readv_from_socket(server, &smb_msg);
+ if (ret > 0)
+ iov_iter_advance(iter, ret);
+ return ret;
+}
+
static bool
is_smb_response(struct TCP_Server_Info *server, unsigned char type)
{